One of those in the gym is missing one of those from Ring
I believe the answer is:
skipping-rope
'one of those in the gym is missing one of those' is the definition.
I can't tell whether this definition defines the answer.
'ring' is the wordplay.
I cannot really understand how this works, but
an anagram of 'ring' is 'ingr' which is located in the answer.
This may be the basis of clue (or it may be nonsense).
'from' acts as a link.
Can you help me to learn more?
(Other definitions for skipping-rope that I've seen before include "Cord (used by playing children)" , "It is swung over head and under foot" , "Cord that's twirled and jumped" , "Cord with handles for jumping over" .)